1. Field of the Invention
The present invention relates to thermal-based electric current cutoff devices and, more particularly, to brackets which are used for mounting the same within electrical devices such as within camera flash units.
2. Description of the Related Art
Thermal-based electric current thermal cutoff devices (hereinafter "thermal cutoff devices") are well known. Such devices are used to control and stop the unexpected and uncontrolled flow of electric current within electronic equipment such as within cameras and camera flash units. In electronic devices that utilize battery-based power supplies, for example, power failures due to short circuits, etc., often result. Such power failures can occur due to broken wires and the like which are caused by movement and impacts realized by electronic devices. When a short circuit occurs, other anomalies can occur within such devices. For example, if a battery unit becomes short-circuited, relatively large "over-current" flows (e.g., 15-30 amperes) can result.
When an over-current situation occurs, the temperature of electronic components within an electrical device can increase rapidly thereby possibly causing damage to the electrical components themselves and to other structures (e.g., plastic and other casing members that support and house electrical components). In some cases, an over-current situation can cause fire if enough current is allowed to flow in an uncontrolled manner for an extended period of time.
Accordingly, to prevent such over-current situations from occurring and to minimize the damage that can result, many pieces of electronic equipment include thermal cutoff devices. Typically, such thermal cutoff devices are mounted on and often adhered to electronic components, such as power supply transformers, transistors, etc., which generate heat. In many cases, thermal cutoff devices are used to protect not only the components to which they are adhered and mounted, but also to protect surrounding components such as enclosures and printed circuit boards, etc.
A typical thermal cutoff device arrangement is shown in FIG. 1 which is attached hereto. In FIG. 1, an electronic component 92 is mounted on a printed circuit board 91. Component 92 is connected to printed circuit board 91 in a conventional way via connecting lead wires 93 which are connected to corresponding conductive patterns 94. A thermal cutoff device 95 is interposed in a current path via terminals 97. Thermal cutoff device 95 is mounted on component 92 via an adhesive 96 such as a glue. Accordingly, when an over-current situation occurs in the circuit (e.g., as a result of a short circuit, etc.), the heat generated by component 92 is transmitted to thermal cutoff device 95 through the adhesive 96. In turn, thermal cutoff device 95 will terminate current flow within the circuit corresponding to component 92.
Although adhesives are widely used to secure thermal cutoff devices to electronic components, several problems are realized. For example, thermal cutoff devices often are adhered to components like component 92 one at a time and, often, by hand. Accordingly, establishing an adhesive coating thickness that is uniform across a production volume of electronic devices is difficult, if not impossible, to achieve. As such, the particular mounting characteristics (e.g., location, relative gap between a thermal cutoff device and corresponding component, etc.) can vary significantly. Additionally, as adhesive 96 often acts as a heat insulating member, the proportion of heat transmission to thermal cutoff device 95 can also differ. And, of course, as adhesive member 96 likely will vary in composition in the context a large product manufacturing run, so too will the heat transmission characteristics of adhesive member 96. Accordingly, when thermal cutoff devices of known characteristics are placed into operation in combination with adhesive mounting arrangements like those illustrated by FIG. 1, their timing and operation characteristics will differ.
Therefore, due to the differences in the thermal response of thermal cutoff devices like thermal cutoff device 95 when mounted with adhesives and the like, erroneous, unexpected operations can result in over-current situations. Furthermore, in the event that thermal cutoff device 95 needs be removed from component 92 (e.g., after a thermal cutoff device has been damaged, for example), it may become necessary to melt or remove adhesive 96. And, after thermal cutoff device 95 has been removed, it may become difficult, if not impossible, to mount another thermal cutoff device which exhibits the same temperature response characteristics as thermal cutoff device 95.
In addition to the problems associated with the prior art thermal cutoff device mounting arrangement described above, there is an obvious problem associated with adhering and mounting a large number of thermal cutoff devices within a given piece of electronic equipment. That is, the sheer number of thermal cutoff devices and the varying types of the same can become costly to install, especially if a relatively large number of thermal cutoff devices are needed in a particular piece of electronic equipment.
Thus, there exists a need to provide an improved device for mounting a thermal cutoff device within a piece of electronic equipment. Such a device should preferably take the form of a bracket. To be effective, such a bracket must allow consolidation of thermal cutoff functionality, allow effective and reliable use of thermal cutoff devices, and allow efficient replacement of thermal cutoff devices. And, to be viable in the relevant marketplace, such a bracket must be capable of being constructed and deployed in cost-effective ways.